From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45528) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cjmYe-0000Oc-Hh for qemu-devel@nongnu.org; Fri, 03 Mar 2017 07:43:41 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cjmYb-0003o2-Eo for qemu-devel@nongnu.org; Fri, 03 Mar 2017 07:43:40 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:47100 helo=mx0a-001b2d01.pphosted.com) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cjmYb-0003nr-9F for qemu-devel@nongnu.org; Fri, 03 Mar 2017 07:43:37 -0500 Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v23CcofG056476 for ; Fri, 3 Mar 2017 07:43:36 -0500 Received: from e06smtp15.uk.ibm.com (e06smtp15.uk.ibm.com [195.75.94.111]) by mx0a-001b2d01.pphosted.com with ESMTP id 28xssu4rx9-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Fri, 03 Mar 2017 07:43:36 -0500 Received: from localhost by e06smtp15.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 3 Mar 2017 12:43:34 -0000 References: <20170302185942.76255-1-pasic@linux.vnet.ibm.com> <20170303132149.34e5906a.cornelia.huck@de.ibm.com> From: Halil Pasic Date: Fri, 3 Mar 2017 13:43:32 +0100 MIME-Version: 1.0 In-Reply-To: <20170303132149.34e5906a.cornelia.huck@de.ibm.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Message-Id: Subject: Re: [Qemu-devel] [PATCH 1/1] virtio: fail device if set_event_notifier fails List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Cornelia Huck Cc: qemu-devel@nongnu.org, "Michael S. Tsirkin" On 03/03/2017 01:21 PM, Cornelia Huck wrote: > On Thu, 2 Mar 2017 19:59:42 +0100 > Halil Pasic wrote: > >> The function virtio_notify_irqfd used to ignore the return code of >> event_notifier_set. Let's fail the device should this occur. > > I'm wondering if there are reasons for event_notifier_set() to fail > beyond "we've hit an internal race and should make an effort to fix > that one, or else we have completely messed up in qemu". Marking the > device broken tells the guest that there's something wrong with the > device, but I think we want qemu bug reports when there's something > broken with the irqfd. > That's why the error is logged. I understand virtio_error like something suitable for indicating bugs. What do you suggest? Forcing a dump? I would rather leave it to the user to figure out how important is the state sitting in the machine and the device, and how much effort does (s)he want to put into recovering from the failure. Halil